Quarterly report pursuant to Section 13 or 15(d)

SHARE-BASED COMPENSATION - Narrative (Details)

v3.22.2.2
SHARE-BASED COMPENSATION - Narrative (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2022
Sep. 30, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]        
Share‑based compensation $ 3,617 $ 2,869 $ 10,031 $ 7,961
Restricted Stock        
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]        
Share‑based compensation 3,600 $ 2,900 10,000 $ 8,000
Share-based payment arrangement, nonvested award, excluding option, cost not yet recognized, amount $ 25,000   $ 25,000  
Share-based payment arrangement, nonvested award, cost not yet recognized, period for recognition     2 years 4 months 24 days  
Restricted Stock | Main Street Capital Corporation 2022 Equity and Incentive Plan        
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]        
Vesting period     3 years